The invention relates to a process for operating a route acquisition system and to a route acquisition system.
A route acquisition system may be included, for example, in a navigation system in a motor vehicle and has, for example, a route acquisition unit, such as a GPS unit. By means of the route acquisition unit, route data of the navigation system can be determined along a driven route of the motor vehicle in the form of electronic routes.
It is an object of the invention to provide a process for operating a route acquisition system as well as a route acquisition system which permits an efficient and reliable storage of electronic routes.
According to a first and second aspect, the invention is characterized by a process for operating a route acquisition system and by a corresponding route acquisition system which comprises a route acquisition unit and a data memory. The route acquisition system is constructed for determining, by means of the route acquisition unit, route data during a movement of the route acquisition system along preset routes and for storing the latter in the form of electronic routes in the data memory. In this case, a preset selection of routes is determined during a preset first operation of the route acquisition system as a function of the electronic routes stored in the data memory. Furthermore, during the first operation, for each route of the preset selection, a number of essentially coinciding routes from the preset selection is determined. In addition, for each route of the preset selection, a route point in time is determined which is representative of a point in time at which the route acquisition system was moved along the preset route. Then a first route time indication relative to a first time unit is determined as a function of the route point in time, and a second route time indication relative to a second time unit is determined as a function of the route point in time. Furthermore, during the first operation, a route evaluation is determined for each route of the preset selection as a function of the assigned number of routes and the assigned route pointing time and the assigned first and second route time indication. Each route of the preset selection is marked with the assigned determined route evaluation. During a preset second operation of the route acquisition system, a size of an occupied storage space of the data memory is determined. As a function of the determined size of the occupied storage space, the respective route of the preset selection is deleted from the data memory as a function of its assigned route evaluation.
This permits a particularly efficient and reliable storage of electronic routes because, as a result of the route deletion, the corresponding electronic routes, in particular, the electronic routes which are evaluated as not necessary, are deleted from the data memory, and therefore sufficient free storage space will exist for new routes to be stored.
In this case, a route typically represents a path between several geographical points. The electronic route is preferably represented by several linked segments or links and is stored in this form in the data memory. In this case, a segment or link represents a route section which differs at least with respect to one preset characteristic from the characteristics of a preceding or following route section; for example, with respect to an obligatory speed, a direction, a road category, such as a federal highway or expressway, etc. The segments of an electronic route are represented, for example, by the route data of the electronic route. The route acquisition system is, for example, arranged in a motor vehicle and is preferably constructed for determining, for each driven route of the motor vehicle, the corresponding route data, as, for example, the form of the segments, and to store this driven route in the form of the corresponding electronic route in the data memory.
The data memory preferably comprises a data bank, in which the electronic routes are stored. With each acquired route, preferably a corresponding electronic route is determined by means of the route acquisition system and is stored in the data memory.
The preset first operation preferably is a normal operation of the route acquisition system, in which the latter is constructed for determining by means of the position indicating unit the electronic route corresponding to the driven route and storing it in the data memory. The preset second operation preferably represents a shutting-down of the route acquisition system before its switch-off. During the shutting-down, the electronic route corresponding to the driven route typically can no longer be determined and stored by means of the route acquisition system.
The essentially coinciding routes each represent a group of routes or a so-called “route cluster”. In this case, the routes assigned to the respective route cluster may deviate from one another within a preset framework. The routes assigned to the electronic routes in the route cluster, along which the route acquisition system was moved in each case, preferably correspond to one another. Thus, for example, the routes of the respective route cluster can be determined to be coinciding if at least one preset quantity of the route data assigned to the routes coincide; thus, for example, if a preset number of segments coincide. A conformity can also be determined if a preset quantity of route data assigned to the routes correspond to one another, taking into account the lengths of the routes.
The determined route point in time of the respective electronic route preferably represents a value of a time stamp, which is stored in a preset format in the data memory, as, for example, in a Unix time format. The respective time stamp is preferably assigned to the first segment of the respective electronic route and represents a point in time at which the route acquisition system was moved along a first route section corresponding with the first segment. The first route time indication preferably represents a time indication relative to the first time unit, which is determined from the assigned route point in time. The second route time indication preferably represents a time indication relative to the second time unit which is determined from the assigned route point in time and differs from the first. For example, the first route time indication represents the minute of the day at which the position acquisition system was moved along the first segment. For example, the second route time indication represents the day of the week on which the position acquisition system was moved along the first segment.
In an advantageous further development of the first and second aspect, the determined size of the occupied storage space is compared with a preset first occupancy level threshold value and with a second preset occupancy level threshold value. The respective route of the preset selection is deleted as a function of its assigned route evaluation if the determined size of the occupied storage space is larger than the preset first occupancy level threshold value and smaller than the preset second occupancy level threshold value. This comparison is carried out in the preset second operation of the route acquisition system, whereby it becomes possible that a deletion of the electronic routes, which are classified as no longer necessary by means of their route evaluation, is carried out only if the data memory is correspondingly occupied. The first and the second occupancy level value preferably represent different memory occupancy levels of the data memory, in which case, the first occupancy level threshold value typically represents a lower occupancy level of the data memory than the second occupancy level threshold value. Preferably, the respective route evaluation is compared with a preset evaluation threshold value and, as a function thereof, the respective route is deleted if the determined size of the occupied storage space is larger than the preset first occupancy level threshold value and smaller than the preset second occupancy level threshold value.
In a further advantageous development of the first and second aspect, routes of the preset selection will be deleted as a function of their assigned route evaluation until the size of the occupied storage space reaches or falls below a preset third occupancy level threshold value. The preset third occupancy level threshold value preferably represents an occupancy level of the data memory between the occupancy levels which are represented by the first and second occupancy level threshold value. The evaluation threshold value can preferably be changed correspondingly as long as the preset third occupancy level threshold value has not yet been reached or there has been a falling below the third occupancy level threshold value.
In a further advantageous development of the first and second aspect, a first evaluation value is determined for each route of the preset selection as a function of the assigned route point in time. In addition, as a function of the assigned route count, a second evaluation value is determined. As a function of the assigned first and second route time indication, a third evaluation value is determined. As a function of the first and second and third evaluation value, the route evaluation is determined. The route evaluation will then be assigned to the respective electronic route of the preset selection; in particular, it is stored with the latter in the data memory. Preferably, the first, second and third evaluation value are multiplied with one another and the resulting product is assigned to the respective route evaluation. The respective evaluation values may, in addition, also be weighted differently. Also, a preset weighting value may be assigned to each evaluation value. It may also preferably be preset that, the lower the respective route evaluation, the more a probability of a deletion of this assigned electronic route will rise.
In a further advantageous development of the first and second aspect, the assigned route point in time for each route of the preset selection is compared with several preset time ranges. In this case, a preset range assignment value is assigned to each time range. It will then be determined to which preset time range the route point in time is assigned. That range assignment value of the determined time range is assigned to the first evaluation value of the respective route. The route point in time represents the point in time at which the assigned electronic route was determined. The farther the route point in time is in the past, the older this electronic route will be. In this case, the range assignment values are assigned, for example, to the respective time range such that, with an increasing age of the respective electronic route, a decreasing range assignment value will be assigned to that first evaluation value. This means, the older the route, the lower the assigned first evaluation value of this route.
In a further advantageous development of the first and second aspect, for each route of the preset selection, the assigned number of routes is compared with a preset route count threshold value. When there is a falling below the route count threshold value, a preset first value is assigned to the second evaluation value of the route. Otherwise, a second value that is dependent on the assigned number of routes is assigned to the second evaluation value. The first value is preferably fixedly preset. The second value is preferably determined such that it is representative of a reciprocal value of the assigned number of routes. The first value preferably is greater than the second value determined as a function of the number of routes. Thus, with a rising number of routes, a decreasing second evaluation value is determined per route cluster. The respective second evaluation value is preferably assigned to each route of the respective route cluster.
In a further advantageous development of the first and the second aspect, route clusters of essentially coinciding routes are determined from the preset selection of electronic routes. From the respective route cluster, a most recent electronic route is determined which has the most recent route point in time. A preset third value is assigned to the third evaluation value of the most recent route. For each additional route of the respective route cluster, the first route time indication of the additional route is compared with the first route time indication of the most recent route, and the second route time indication of the additional route is compared with the second route time indication of the most recent route. As a function of the comparison, a degree of a time-related correspondence relative to the first and second route indication between the most recent route and the additional route is determined. As a function of the determined degree of the time-related correspondence, the third evaluation value is determined and assigned to the additional route.
A fixedly preset third value is assigned to the most recent route of the respective route cluster, which third value preferably represents a maximal value of the third evaluation values within the respective route cluster. The respective degree of the time-related conformity is preferably determined as a function of a first and a second coincidence value. The first coincidence value is determined as a function of a preset normal distribution relative to the first route time indication of the respective additional route. A first preset assignment value is preferably assigned to the second coincidence value in the case of a conformity of the second route time indication of the respective additional route with the second route time indication of the most recent route. The first preset assignment value may, for example, be a maximal value of the second assignment values. If the second route time indication of the respective additional route corresponds to the second route time indication of the most recent route in a preset category, as, for example, a weekday, a weekend day, a holiday, a second preset assignment value is assigned to the second coincidence value. Otherwise, a third preset assignment value is assigned to the second coincidence value. The third preset assignment value may, for example, be a minimal value of the second assignment values. The second assignment value preferably is smaller than the first and larger than the third predefined assignment value. Preferably, a decreasing third evaluation value results from an increasing time-related conformity relative to the first and second route time indication between the most recent route and the additional route.
In a further advantageous development of the first and second aspect, a route length is determined during the preset first operation of the route acquisition system for each route of the preset selection. The route evaluation is determined as a function of the determined route length. This means that the route evaluation for each route of the preset selection is determined as a function of the assigned number of routes and the assigned route point in time and the assigned first and second route time indication and the assigned route length.
In a further advantageous development of the first and second aspect, a fourth evaluation value is determined for each route of the preset selection as a function of the assigned route length. The route evaluation is determined as a function of the fourth evaluation value; i.e., the route evaluation for each route of the given selection is determined as a function of the first, second, third and fourth evaluation value. The route evaluation is preferably determined as a product of these evaluation values. In this case, it may preferably be preset that, the lower the respective route evaluation, the more a probability of a deletion of this assigned electronic route will rise.
According to a third and fourth aspect, the invention is characterized by a process for operating a route acquisition system and by a corresponding route acquisition system which comprises a route acquisition unit and a data memory. The route acquisition system is constructed for, beginning from a respectively preset start position, acquiring route data by means of the route acquisition unit during a movement of the route acquisition system along a respectively provided route and storing these route data in the form of an electronic route in the data memory. Here, it is first determined whether the route detection system has reached a preset destination position. As a function of reaching the preset destination position, the route data are determined from the data memory, which were acquired during the movement of the route acquisition system. As a function of the preset start and destination position and the determined route data, a comparison route is determined as a function of the preset navigation data. Comparison route data of the determined comparison route are compared with the determined route data. As a function of the comparison, one or more determined route data are corrected.
This can make it possible to store the routes in a particularly efficient manner in the data memory. In this case, for example, superfluous route data can be deleted and/or faulty or missing route data can be replaced by the comparison route data.
Here, the route typically represents a path between several geographical points. The electronic route is preferably represented by several mutually linked segments or links and is stored in this form in the data memory. A segment or link represents a route section which differs at least with respect to one preset characteristic from the characteristics of a preceding or following route section; for example, with respect to an obligatory speed, a direction, a road category, such as a federal highway or expressway, etc. The segments of an electronic route are preferably represented by the route data of the electronic route. The route acquisition system is, for example, arranged in a motor vehicle and is preferably constructed for determining, for each driven route of the motor vehicle, the corresponding route data, as, for example, the form of the segments, and to store this driven route in the form of the corresponding electronic route in the data memory. Furthermore, the route acquisition system can, for example, also be used in portable navigation systems or smartphones.
The data memory preferably comprises a data bank in which the electronic data are stored. In addition, the preset navigation data can be stored in the data memory. Preferably, a corresponding electronic route is determined together with each acquired route by means of the route acquisition system and is stored in the data memory.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.